You need to use some javascript. Here's the function I use for opening new windows:
function openNewWindow(URL) {
day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=1,location=0,statusbar=0,menubar=0,resizable=1,width=690,height=575,left = 170,top = 90');");
}
Then you just call it like:
<a href="javascript:openNewWindow('mypage.php');">link text here</a>
edit: For some reason it's showing up with a space between java and script in that link. Do not use a space 🙂